Distraction osteogenesis is the process of lengthening bone tissue by cutting a bone segment from a source bone and gradually moving the bone segment away from the bone. The ends of the bone segment and source bone along the cut line are spaced apart to allow the formation of new bone tissue within the gap between the bone segment and source bone. As the bone segment is gradually moved away from the source bone, new bone tissue continues to grow between the bone segment and source bone until a desired length of the source bone, e.g., a desired increase in the length of the source bone, is reached. After the desired bone length is reached, the new bone tissue is allowed to heal until the tissue reaches an appropriate density the same as or similar to the source bone.
Traditionally, distraction osteogenesis techniques were limited to the field of orthopedics. Recently, however, distraction osteogenesis techniques have been applied to correct deformities of the jaw. Such jaw bone distraction techniques typically involve cutting away a bone segment from a source jaw bone, e.g., one of the maxilla or mandible jaw bones, securing a distraction device to the bone segment and the source jaw bone, and adjusting the distraction device to push the bone segment away from the source jaw bone.
Conventional jaw bone distraction techniques and devices suffer from several drawbacks. For example, pushing a bone segment away from the source jaw bone reduces the force vector control of the moving segment. Additionally, current bone distraction devices that push the bone segment away from the source jaw bone are typically attached or embedded within a patient's tissue, which can limit access and adjustment of the distractor and increase the risk of infection. Further, current bone distraction devices have a single threaded rod that facilitates adjusting of the devices. Such a configuration results in a distraction device with a limited action to length ratio, e.g., range of motion of the distraction device to overall minimum length ratio. In other words, the distance the distractor is able to push the bone segment is relatively small compared to the minimum overall length of the distractor itself. This results in a large device with a small range of motion.